How is delayed sleep-wake phase disorder (DSWPD) diagnosed?
DSWPD is diagnosed based solely on a description of the symptoms and sleep logs. Sometimes a non-invasive wrist-watch-like device called an actigraph may be used to confirm rest-activity rhythms. An overnight sleep study (polysomnogram) may be recommended to rule out the presence of any other sleep disorders. Sophisticated tests of melatonin or core temperature rhythms are generally reserved for research purposes.